1. Field of the Invention
This invention relates generally to economical, easily transported and rapidly set up chairs suitable for large gatherings such as parades, sporting events and parties; and more particularly to a collapsible, disposable chair of corrugated fiberboard or like generally planar recyclable material.
2. Prior Art
Many efforts have been made to provide a satisfactory chair that can be formed from corrugated cardboard or like internally-reinforced sheet stock, to take advantage of the low cost, weight and bulk of the material--as well as its inherent (but nonisotropic) compressive and tensile strength. Such efforts, while successful conceptually, generally have foundered commercially on the difficulty of simultaneously satisfying two conflicting conditions.
One one hand, corrugated fiberboard is weak with respect to bending or folding along the "grain" (i.e., the direction of the fluting). A practical design must provide enough bracing to overcome this inherent weakness.
On the other hand, a practical design--particularly in the current era of high labor cost--must be simple enough to absolutely minimize handwork. Manual fabrication or assembly operations rapidly run up the overall cost of manufacture or use. The same is true even of disassembly operations, for fiberboard chairs usually must be knocked down preparatory to reuse or even to economic disposal.
Prior-art fiberboard chairs are disclosed in literally dozens of United States patents. Of these, a representative pertinent sample includes U.S. Pat. Nos. 2,049,659, 2,806,514, 3,168,347, 3,312,503, 3,250,570, 3,331,634, 3,463,546 and 4,085,970.
As can be seen at a glance, all these designs involve multiple compound folds and contours, tab-and-slot attachments, mutually slotted cross-brace inserts, and other elaborations. Some of these designs may be viable for small-volume applications such as children's furniture, in which a few minutes of assembly work (usually assigned to the retail consumer) may be commercially acceptable.
For high-volume applications such as parade or ballgame seating, however, in present economic terms such designs are entirely unacceptable. In each case the care and time required for assembly, disassembly or both renders the design impractical.
One prior configuration that is commercially and industrially much more sophisticated appears in U.S. Pat. No. 4,556,253, issued Dec. 3, 1985, to Geneve et al. The base of this chair is a glued tube of irregular form--apparently a nonequilateral hexagon. The seat, rather elaborately contoured and shaped, has double thickness.
Geneve and his coinventors have apparently gone to some length to produce a fiberboard chair that has the look of comfortable furniture and may actually be ergonomically sound. Nevertheless their finished chair is all one piece, collapses flat for storage and transport, and can be made from a single die-cut and scored blank.
Thus U.S. Pat. No. 4,556,253 represents quite an accomplishment. It is a clear and plainly useful advance over the prior art, but it does leave some areas for improvement.
First, the Geneve chair requires a relatively elaborate blank. As can be seen from Geneve's FIGS. 2a and 2b (which show the chair in its folded-flat condition), he uses double-thickness seat and backrest panels, and "optional" reinforcing panels A, B, C, A', B' and C'.
Although Geneve characterizes the six panels just mentioned as "optional," he also indicates that he "prefers" to provide them to obtain satisfactory strength of the finished chair when using general industrial-grade fiberboard. It appears fair to infer that the broad, open and irregular plan of the chair base naturally results in some considerable structural weakness, which is best compensated by providing the reinforcing panels at the bottom edges--and by providing the double seat and backrest panels.
Secondly, because of its complicated shape, the chair requires relatively extensive machine (or personnel) time for initial preassembly. Special attention is required for gluing or other securing of at least three parts of Geneve's chair: (1) the irregularly shaped, irregularly angled friction and slot-engagement panels G, H and I; (2) the "optional" reinforcement panels A, B, C, A', B' and C'; and (3) the tube-completion tab M (FIGS. 1 and 2a).
The tab M is particularly troublesome, though it appears innocuous in Geneve's drawings, for it must be folded back on itself at 180 degrees in preparation for gluing. Stable, reliable machine gripping of such a tab for gluing requires a much wider tab than Geneve's drawings suggest.
Correction of this problem by widening the tab, however, tends to increase material use excessively. This is particularly important in view of the waste material that extends to the full height of the blank, above the tab M.
Moreover, setting up automatic machinery for a reliable grip is especially tricky, even if the tab M is wider, because the tab M extends less than the full height of the chair blank. Hence the Geneve design leads inevitably to a "fussy" adjustment of the machine, or as it might be called in the industry, a "touchy run."
Experienced fiberboard fabricators know that such special projects carry a very dangerous potential for delaying--and consequently losing--the profitable projects of their regular customers. The latter are typically long machine runs on a short schedule, manufacturing conventional boxes and the like.
Seasoned operators in the fiberboard production field are accordingly wary of tying up their facilities with projects requiring special attention. They are reluctant to accept such jobs, even with price premiums for the extra work. A machine operation such as assembling the Geneve chair, as a practical matter in the industry, may be simply refused.
Even if performed manually, the gluing of Geneve's tab M is difficult. The tab must be folded to its 180-degree folded-back position, and then held and glued simultaneously. The economic impact of such design details on practical implementation of an invention cannot be overemphasized.
Thirdly, the Geneve chair is relatively bulky to store and ship, even in its folded-flat condition. This is due to the fact that in that condition the seat and backrest panels extend upward well beyond the top of the chair back. In particular, the narrow rib or webbing BB (FIG. 1) defines the maximum height of the chair back, but the seat and backrest panels K, N, O, P, Q and R apparently extend a foot or more past that webbing.
Fourthly, even putting aside manufacturing, preassembly and handling costs, it may be difficult in practice to realize the theoretical economics of the Geneve chair. Here the sticking point may be in the very sophistication that confers upon the chair its various advantages.
Specifically, the Geneve chair is apparently quite tricky to set up. The reason, again, is clear from examination of FIGS. 2a and 2b.
As those drawings show, the fold lines that separate the six walls of the chair base do not extend upward into the seat and back panels. Therefore, notwithstanding Geneve's text at columns 7 and 8, one cannot simply open out the base portion to its hexagonal form without simultaneously folding the seat panels down.
To properly accomplish those two tasks simultaneously, however, would appear to require considerable dexterity and practice.
Furthermore, it is necessary to open the base to the correct hexagonal plan, to match the descending seat panels Upon reflection, and without intending in the least any disrespect, it will be realized that establishing a correct mental model of an irregular hexagon may be asking a great deal of the type of personnel who may normally be engaged to set up cardboard chairs along a parade route.
In sum, it is not at all clear that unskilled or semiskilled laborers could quickly learn to set up a large number of such chairs in a hurry. Yet economics obviously militate against damaging an unduly large fraction of the inventory during setup. Even well-practiced personnel would surely require five or ten seconds, at the very least, per chair.
The foregoing comments are believed to be valid even without taking into consideration the required engagement of Geneve's locking tab Z with its mating slot Z' for assembly--and disengagement of those elements for disassembly. These tabs and their mating slots, besides taking time to engage or disengage, will shortly become worn and then damaged, severely limiting the reusability of the chair.
The same appears true, though perhaps to a lesser degree, of the notches Y and mating notches Y' (FIGS. 1, 8 and 10). These notches must be meshed at each assembly, and unmeshed at each disassembly, of the Geneve chair.
Another prior patent that may be pertinent to our invention since it discloses a chair-shaped fiberboard display shelf, although it is not a chair at all, is U.S. Pat. No. 4,279,375. That patent issued July 21, 1981, to Gardner and is assigned to Container Corporation of America.
The Gardner patent is actually in a different field, namely that of retail-goods display paraphernalia. More particularly, Gardner discloses a combination shipping carton and display shelf.
As is best shown in Gardner's FIGS. 1 and 2, his invention is a glued rectangular tube (note glue tab 16) that has a horizontal score 35 across the front panel 40, 10. It also has on each side a diagonal score 39 running from the upper rear corner of the tube downward to meet the horizontal front score 35 at the front corner of the tube.
As best shown in Gardner's FIGS. 6 and 7, the upper portion 46-44-42-40 of the front panel 10-46-44-42-40 can be folded backward, downward and inward, relative to the tube, to form a flat shelf. The forward upper triangular corner 48-50 of each side wall simultaneously is doubled over along the scores 39, to lie flat against the remaining part 12 of the side wall, but inside the tube.
As a result the flat shelf 46-44-42-40 is hung at its lateral edges (previously the vertical corners 29, FIG. 1) by the triangular panels 48-50, from the fold lines 39. By selection of a forty-five-degree angle for the fold lines 39, Gardner causes the rear edge of his shelf to just touch the inside of his rear panel.
To permit the front panel to fold inward as described, it is necessary to account for so-called "lost motion" that occurs only during the folding. That is to say, the upper portions of the panels must be temporarily deformed out of their rectangular-tube plan. To permit this buckling, best shown in Gardner's FIG. 6, he has provided additional diagonal scores 37 in the upper portion 46-44-42-40 of his front panel.
Such additional scores clearly weaken the shelf. Since it is used only for merchandise, however, any such weakening may be immaterial.
Both Geneve and Gardner disclose vertical glued-tube constructions, and such constructions generally are known. Neither Geneve, nor Gardner, however, provides any direct support in the nature of an internal pillar or pedestal beneath the support surface--that is, beneath Geneve's seat panel or Gardner's display-shelf panel--for the weight to be disposed upon that support surface.
Various prior-art chairs mentioned in the patents enumerated earlier do provide internal pillars, but there is no suggestion in any of the patents discussed so far of any way to provide such an internal pillar without destroying the flat-knockdown feature of the Geneve chair--or for that matter the general utility of the Gardner invention as an open-construction shipping carton.
Yet another teaching of prior art that may be pertinent to our invention is also in the field of shipping containers, although it is not discussed, disclosed or even suggested by Gardner. That teaching consists of supplying an internal crosswise panel for a vertical rectangular glued tube, parallel to two of the walls of the tube--the so-called "bridge box" construction.
The internal panel is often glued or otherwise secured in position. Its primary purpose is to divide products contained in the box and to add stacking strength.
As the internal vertical panel parallels the external walls of the glued tube, it need not be removed to fold the tube for shipment, etc. Rather, the inside panel folds down in parallelogram fashion, along with the tube itself.
We are not aware of any prior-art suggestion that the three groups of teachings described above might in any way be combined. Gardner's combined display rack and shipping carton is neither in need of nor compatible with an added inside panel. (In addition, his shelf is weakened by diagonal scores; these factors together leave his configuration entirely inadequate for seating applications.) Geneve's chair design, considering the hexagonal plan and nonhorizontal seat, does not appear to allow installation of a parallelogram-style inside panel; and as earlier noted his invention is already excessively elaborate and "touchy" to fabricate.
Thus the prior art fails to satisfy the commercial need for a chair that can be made and assembled very economically at high volume from fiberboard or the like, to take advantage of the favorable properties of such material while providing adequate strength.